The NOEMA array was used in configuration A with 8 antennas on 23 and 30 December 2016 to observe the spectral band 204.0–207.6 GHz towards the Cep E-mm protostellar system, as part of the Large Program SOLIS [1]}. The field of view of the interferometer was centered at position \(\alpha \) (J2000)= \(23^{h}03^{m}1300\)  \(\delta \) (J2000)= \(+61\)\(^{\rm o}\) 422100.
The wideband receiver WIDEX covered the spectral band 204.0–207.6 GHz with a spectral resolution of 1.95 MHz (\(\simeq 2.8\hbox{\hspace{1.99997pt}km\hspace{1.99997pt}s$^{-1}$}\) ), which includes the rotational transition SO \(N_J\) = \(5_4\) –\(4_3\)  at 206176.005 MHz. The spectroscopic parameters of the transition are taken from CDMSCDMS database: https://cdms.astro.uni-koeln.de/cdms/ (Müller et al. 2005).
The precipitable water vapor (PWV) varied between 1mm and 2 mm (between 2mm and 4mm in the second night) during the observations. Standard interferometric calibrations were performed during the observations: J2223+628 was used for both amplitude and phase calibration. Bandpass calibration was performed on 3C454.3. Calibration and imaging were performed by following the standard procedures with GILDAS-CLIC-MAPPINGhttp://www.iram.fr/IRAMFR/GILDAS/. The emission of the SO \(N_J\) = \(5_4\) –\(4_3\)  line was imaged using natural weighting, with a synthesized beam of \(0.52\times 0.41\)  and a position angle PA of \(359\hbox{\hspace{1.99997pt}$^{\rm o}$}\)  (see Tab. REF ). Self-calibration was applied to the data.
The shortest and longest baselines were 72m and 760m, respectively, allowing us to recover emission at scales up to 12. The primary beam of the interferometer (\(\approx 24.4\) ) allowed us to recover emission up to \(\sim 12\)  (\(10^4\)  au) away from protostars Cep E-A and Cep E-B, while the synthesized beam gave access to spatial scales of \(\approx 400\)  au.
